Construction for radio receiving inductances



Aug. I4, v1928. 1,680,851

T.H. BRENNAN CONSTRUCTION FOR RADIO RECEIVING INDUCTANCES Filed'April 27. V:1925 2 Sheets-Sheet l Aug. 14, 1928.

T. H. BRENNAN CONSTRUCTION FOR RADIO RECEIVING INDUCTANCS Filed April 27. 1925 2 Shoots-Sheet 2 MELA@ are) rar-.eared Aug. 14, iezs. i lfdl UNITED OFFlCE.

THOMAS H. BRENNAN, GF CHICAGO, ILLINCIS.'

CONSTRUCTION FOR RADIO RECEIVING INDUCTANGES.

Vi'lpplcation filed. April 27, Serial No. 26,025.

My invention relates to a construction for Andrew F. Henninger Jr., for Letters radio receiving inductances, designed espe- Patent of the United States, filed August 11. cially to minimize energy depletion through 1924, Serial No. 731,861 which became Let-l dielectric absorption and leakage in the inters Patent No. 1,551,392, dated August .25, so

ductances preceding the tube and to increase 1925.

selectivity, range of reception and as well to According to the preferred embodiment of improve clarity of tone, and the main obmyv invention'as illustrated in the accomject of my invention is the provision of an panying drawings, the secondary coil 8 is improved receiver of this character which Supportedin inclined position and upon an ,65

10 will be economical in manufacture and highangular bracket 12 which, as best shown .in ly efficient in. use. Fig. 6, is threaded upon a sleeve member' 13 Other objects will appear hereinafter. between a bushing 14 and a securing nut 15, The invention consists in the combinations both of which are threaded upon said sleeve and arrangements of parts hereinafter de- 13. The bushing 14 is arranged in a panel 'zo 15 scribed md Claimed, board 16 or other suitable support. Extend- The invention will be best understood by ing through and rotatable in the sleeve 13 is a reference to the accompanying drawings, shaft 17 to which is secured on the outer forming a part of this specification, and in side of the panel 16, a turning knob 18 carrywhich, ingthe usual dial member 19. To t-he in- Z5 zo Fig. 1 represents a. side elevational view nel' protruding end of the shaft 17 is secured of my improved construction for receiving an angular bracket 20 carrying a pair of ininducmnqes; Y Y sulatioii strips 21 which cross and embrace Fig. 2 represents a central cross sectional the windings of the primary coil 22. The inview taken on the line 2--2 of Fig. 1; sulation strips 21 are preferably made of 8o y 25 Fig. 3 is a front end view, taken on the line bakelite and one of these strips is suitably 8*8 of Fig. 1, parts being shown in section; giooved at 23 to provide a channel foi the Fig. 4 is a rear end view, taken approxireception of the windings of thel coil, which mately on the line 4-4 of Fig. 1; .y said windings are held rigid in properly Fig. 5 is a fragmental front elevational wound relation by the clamping action of 235 EWS said strips. For securing the strips 21 to- Fig. 6 represents a central vertical section, gether in proper clamping relation, I preftakcn approximately on the line 6-6 of Fig. erably pass bolt members 24 therethrough, to 5, the secondary winding and supporting which bolt members are applied the usual frame therefor being only partially shown; adjusting nuts 25. o0 and l. Under this arrangement, the primary coil Fig. 7 represents a cross section taken on 22, which is of less diameter than the secthe line 7-7 of Fig. 6. ondary coil 8, is supported for movement lilith more particular reference to the and angular adjustment within the windings y parts illustrated in the accompanying drawof the secondary coil 8; and owing to the 95 40 ings, the numeral 8 denotes a secondary coil angular relationship betweeny the secondarywound in cylindrical form, the windings coil Sand the position of the rotatable shaft thereof being held and embraced at inter- 17, the angular bracket 2O so supports the vals by pairs of crossing members or strips primary coil 22 that the same upon the turni 9 made of any suitable insulation material, ing ofthe shaft 17 may be moved from a 100 preferably of bakelite. The extremities of position in which it is' concentric with the these insulation crossing strips are bolted secondary coil to a position in whichit is at upon end supporting rings 10 Aand 11 as best right angles to the windings of the saidsecillustrated in Figs. 1 and 2. This secondary ondary coil. y It being unnecessary to move coil 8 is thus embraced by the spaced apart theprimary coil more than 180 degrees or 105 pairs of crossing members 9 which aord the from Va position concentric with the secondonly solid dielectricscontacting with the arycoil to a position at right angles therey windings thereof, it being observed that this with. I preferably provide means for limitcoil is thus supported on and spaced from ing the turning movement of the rotary the end rings 10 and 11. This secondary shaft 1.7. This limiting means comprises a 110 coil and its mounting is more fully illuspin 26 on the shaft 17 and a circumferen-V trated and described in the application of' tially extendingslot 27 in the sleeve 13, the

said pin being adapted to work in said slot and to engage the end walls thereof as abutments whereby to limit the turning of the shaft. The free ends of the coil 22 are taken rearwardly through the secondary coil 8 and secured to suitable soldering lugs 28 as best illustrated in Fig. 3'.

It will be observed that the primary coil 22 is entirely open to the air except at the points where it is confined by the crossing strips 2l. By this construction I provide a minimum of solid dielectric and a maximum of atmospheric dielectric, thereby reducing losses by absorption and leakage Vto a minimum while providing a clear space for the maximumtransfer of energy. In this connection, it is also to be 'observed that yno shellac, varnish, cement or other compound is used to hold the coil since the windings thereof are rigidly held in proper positionby the crossingl strips 2l.

Secured to the rear ringl il is a hinge memberQQ carrying insulation strips 30 which cross and embrace a tuning inductance or coil 3l. y rlhis tuning` coil, like the primary coil is entirely open to the air vexcept at the points where it is confined by the crossing strips 3Q. The coil 3l is of less diameter than the secondary coil S and owing to its hinged engagement with the ring l1 it may be moved into various positions of adjustment'with respect to the secondary coil. The ends of the coil 3l are brought to suitable soldering` lugs 32.

`From the foregoing description taken in connection with the accompanying drawings, it will be understood by'those familiar with radio receiving sets that- I have not 'only provided a very simple inductance construction, in which air alone is thel dielectric except at the points where the wind-ings are embraced by the crossing strips, but one that provides for a maximum transfer of'energy through the coils preceding the detector, whereby to increase the range of reception, volume and improve the clarity of the tone.

IVhile I have illustrated and described the preferred form of construction for carrying my invention into effect, this is capable of variation and modification withoutdeparting from the spirit of the invention. I, therefore, do not wish to be limited to the precise detailsof construction set forth, but

desire to avail myselfof such variations andV modifications, as come within the scope of the appended claims.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

.1. In a construction for radio receiving inductances, the combination with a bracket `member, of a shaft having rotatable support Aing the second named coil from said bracket member; an insulation strip hinged to said supporting means; and a third coil having its `winding held by said hinge strip and adapted tobe swung into various positions of adjustment with respect to said second named coil, substantially as described.

2. In 'a construction for radio receiving inductances, the combination with a bracket member, of a frame including insulation strips carried by said bracket member; a

cylindrical coil having its winding held on said insulation strips; an insulation st ip hinged to said frame; and a coil h ving winding held by and positioned on said hingedinsulation strip and otherwise open to the air as a dielectric and adapted to be swung into various positions of adjustment with respect to said i'irst named coil, substantially as described. Y e

3. A construction for radio receiving ductances including a frame provided with end pieces; a cylindrical coil carried by the frame between the end pieces; a bracket attached to one end piece and provided with a bearing; a shaft rotatable in said bearing; an insulation support projecting from the shaft inwardly ofthe frame; a coil having its winding mounted on said insulation sup.

THOMAS ll. BR" QNNA N. 

